Downhole Robotic Micro-Drilling System

ABSTRACT

The invention relates to the completion and enhancement of oil and gas wells. The invention provides for a downhole tool which: enters vertical or horizontal wells located adjacent to the oil and gas bearing formation, parts the casing and extends outward forming micro-boreholes necessary to remove residual oil and gas which remain in place. After the initial fluid production has been harvested, the invention can be employed on new or old wells and can operate in all conditions which wells encounter during the standard drilling process. 
     The process of micro-holes can replace the process known as “fracking”. Fracking is being employed; however the process is being reviewed due to safety of human life. The invention employs special alloys and procedures to form the extended reach micro-boreholes.

CROSS REFERENCE TO RELATED APPLICATIONS

[The application is a non-provisional, and claims priority benefit, of U.S. Provisional Patent Application Ser. No. 61/630,205 filed Dec. 6, 2011 which is incorporated herein by specific reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention disclosed and taught herein relate to the producing of oil and gas wells. The invention provides a method to place micro-boreholes into an oil and gas formation employing a robotic micro-drilling method.

2. Description of the Related Art

U.S. Provisional Patent Application Ser. No. 61/630,205 discloses the micro-drilling system herein a radius turn is required to transform the vertical borehole to a horizontal borehole.

U.S. Provisional Patent Application Ser. No. 61/630,205 discloses the method in which the casing is parted and the radius micro-boreholes are provided.

The invention disclosed and taught herein is directed to an improved method to provide micro boreholes employing a robotic control system.

BRIEF SUMMARY OF THE INVENTION

The oil and gas industry has found new production in areas, which are considered “harsh”. The areas of new discovery are the Arctic, deepwater, and areas prone to citizens unrest. Recently, the formations known as “shale” are being developed employing a process know as “fracking” for completion purposes. This process, for the most part, is not controlled and the process is being reviewed as a system, which will affect the health of humans.

The invention described in the application relates to a method to enhance oil and gas formations to yield high production rates. The system also replaces the fracking process with a safe and controllable method of completion. The invention allows boreholes to be placed in a controlled location and extends from the main borehole to a required length. The micro-holes are designed to provide individual channels to reach the oil and gas reserves.

Studies have indicated that the size of the micro-hole can be provided to release a certain portion of reserves. High concentration of the boreholes allow for greater inflow of production. The invention is based on placing micro-holes in a lateral mode extending from the main borehole. The invention also requires that the micro-holes are made at a rapid pace and that 20 micro-holes can be provided with only one trip into the main borehole.

It is also the intention of the invention to provide composite inserts in the casing string to allow rapid entry into the formation and that the mill/bit's effective life is extended due to the carbon fiber material properties. The casing inserts also provide landing nipples to position the micro-hole boring tool. The landing nipples are located to allow the micro-holes to be provided employing a robotic system. The invention further describes a method where the micro-hole can be separated from other holes and can be programmed to open or close on demand. The micro-holes can be directed in any direction.

Due to the formation strength, different methods of formation cutting may be chosen. In soft to medium strength formations, the micro-hole can be jetted employing high-pressure fluids. In harder formations, the micro-holes are made using special cutters, designed to cut the hardness of the materials.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a cross-section of the earth, which shows the earth's surface and the oil and gas formation. The illustration also shows a surface workover rig, casing string and the downhole invention tool.

FIG. 2 illustrates a detail of the oil and gas formations. The casing is illustrated located at the bottom lower section of the oil and gas formation. The drawing illustrates the location of carbon fiber inserts.

FIG. 3 illustrates a casing insert, which is mounted into the standard steel casing string. The insert has steel threaded connections and an axial body made of carbon fiber or other suitable material (non-metallic). The insert also is equipped with a landing nipple to be used in the positioning of the downhole tool invention.

FIG. 4 illustrates the cased borehole located at the lower elevation of the formation. Lateral boreholes are illustrated extending from the casing upward towards the upper level of the formation. The lateral boreholes are positioned in one direction as shown.

FIG. 5 illustrates a typical surface unit, which supports the downhole operations. The wheeled mounted unit is equipped with all components required for the operation of the downhole robotic tool.

FIG. 6 illustrates a typical location surface layout showing the workover rig, the invention's downhole tool support unit, tank and high-pressure pump.

FIG. 7 illustrates the engine and pumping system of the surface support equipment.

FIG. 8 illustrates the automatic control panel, which is located in the surface unit. The control panel is employed as a progressing method regarding the downhole tool actions.

FIG. 9 illustrates the high-pressure swivel arrangement. The swivel allows the fluid pressures to be transferred into a rotating workstring. A standard oilfield power swivel is converted to provide the high-pressure to a maximum of 20,000 psi.

FIG. 10 illustrates the hydraulic diagram of the downhole tool invention.

FIG. 11 illustrates the tool anchoring system. This system is employed when insert units are provided.

FIG. 12 illustrates the magnetic hole cleaner.

FIG. 13 illustrates the tool exit component.

FIG. 14 illustrates the hex orientation sub assembly.

FIG. 15 illustrates the hex bend radius guide tube. FIG. 15A illustrates the bearing assembly of the threaded connection on one end of the hex guide tube. FIG. 15B illustrates the disconnect device on the opposite end of the hex guide tube.

FIG. 16 illustrates the outer body and top lock assembly.

FIG. 17 illustrates the mill/bit unit.

FIG. 18 illustrates the lower extension tube. FIG. 18A illustrates the extension tube connection.

FIG. 19 illustrates the upper section of the extension tube.

FIG. 20 illustrates the safety tube for the upper extension tube.

FIG. 21 illustrates the assembled downhole tool unit with guide and extension tubes.

FIG. 22 illustrates a typical formation, casing and guide tube extended.

FIG. 23 illustrates a typical formation, casing and the guide tube extended with extension tube extended.

FIG. 24 illustrates a typical formation, casing and a completed micro-hole.

DETAILED DESCRIPTION OF THE INVENTION Detailed Description of the Preferred Embodiment

The basic purpose of the invention provides for the manufacturing of micro-boreholes into oil and gas formations for enhancement of the oil and gas production. The preferred embodiment is described as follows:

FIG. 1 illustrates a typical cross section of the earth. The surface 3 supports the control unit 2 and the workover rig 1. A casing string 4 is considered the main borehole. The top of the formation 5 and lower level of the formation 6 defines the area for the production of the oil and gas. The casing “turn” 7 is illustrated from a vertical mode to a horizontal mode. The horizontal leg of casing 8 is illustrated in the main borehole at the production level. The main borehole terminates at location 9.

FIG. 2 illustrates the typical oil and gas formation. The upper formation level 5 and lower formation level 6 defines the thickness of the formation. The horizontal casing leg 8 illustrates installed casing inserts 13.

FIG. 3 illustrates a typical casing insert 13 having components of steel upper connection 11 and a lower steel connection 14. A carbon fiber tube 12 is connected by a bonding method to the steel connection 11 and 14. A landing nipple 15 is provided and connected to the casing insert 13. A threaded connection 16 is provided to connect the assembly to the casing string. Hence, casing inserts 13 can be mounted on demand within the casing string. The casing inserts 13 have a landing nipple 15, which allows the downhole tool to be located and locked. The nipple has a special opening, which causes the tool to be located axially. The nipples also prevent the tool from rotating.

The invention's purpose is to provide cluster micro-holes 10 as illustrated in FIG. 4. The micro-boreholes are placed through the casing inserts 13 throughout the length of the horizontal casing leg 8. The downhole invention supported by the surface unit provides a method to provide the micro-boreholes.

FIG. 5 illustrates a control surface unit. The unit is fitted with a high pressure hose assembly 30, a control room 17, an air compressor 18, a fluid manifold 19, a filter unit 20, a high-pressure pump 21 and a diesel engine 22. The surface unit supplies the necessary power and control for the downhole operations. The High Pressure Reels 35 are employed for proper care of the hoses. The reels are powered and have a centerline high pressure swivel to introduce the fluid into the hose. The tools and equipment may be handled by the full rotating crane 24. The crane 24 is powered by a hydraulic power swivel. The control surface unit also has a tool storage area 23 which is employed to store and transport various spare parts for the operations of the surface unit.

FIG. 6 illustrates a typical layout of the surface equipment. The workover rig 26 is adjacent to the well center 25. The invention surface control 27 is also adjacent to the well center. A fluid tank 28 provides a container for the completion fluids. The fluids are pumped to the surface unit and the fluids are filtered. The fluid is then pumped to the downhole tool at a pressure of 20,000 psi. A general area is provided for pipe racks and tool make-up 29. The processed fluid is filtered to a level of 5 microns via a bag filter. The filtered material exits the filter unit to the high-pressure pump.

FIG. 7 illustrates the plan view of the surface support unit. A diesel engine 22 drives a high-pressure pump 21. The pumped fluid is transferred into the manifold 19. Control unit 36 directs the fluid to different areas of the support equipment. The controls and valves are air operated. The air compressor 18 produces the compressed air. High-pressure hose 30 supplies the fluid to the rotary seal located at the well center. The Fluid Filter Unit 20 is the system which removes solids from the pumping fluids to meet a 5 micron cut level.

The downhole tools are controlled via the system mounted on the control console unit 36 of FIG. 8. The diesel engine speed is controlled by Item 46. The pump pressure is controlled by Item 45 and the work string speed (swivel speed) is controlled by Item 44. Indicator lights 43 are provided to allow the operator the real time conditions of the process.

The drilling of the micro-boreholes is supported by a power swivel 47 of FIG. 9. The swivel is suspended via the rig's derrick and hoisting gear. The power swivel is driven by a hydraulic motor 53 and a speed reducer 51. High-pressure fluid is pumped to the swivel entering at coupling 52. The swivel is equipped with a high-pressure swivel 48, a pressure tube 49 and the high pressure fluid exits the swivel at 50 via a connection to the work string. The swivel is rated for a minimum of 20,000 psi operating pressure.

The fluid enters the work string 59 from the power swivel 47 at a location above the drill floor, as seen in FIG. 10. A pressure safety valve 58 is a check system, which prevents back flow from the oil and gas formation. The work string 59 is made of alloy steel having an operating pressure of 20,000 psi, minimum. The pipe section is in approximately 30′ lengths and is connected by threaded joints.

Above the downhole tool is an extension tube 60, which has a length between 30′ and 1000′. The extension tube 60 has flush internal connections which allow a constant outside diameter. The upper extension tube is connected to the lower extension tube 61. The lower extension tube 61 is constructed of a special alloy material. The lower extension tube 61 has lateral spherical supports, which are welded to the tubes via an electron-beam welding process. The lateral support spheres cause the extension tube 61 to have greater compression strength to conduct the drilling process. The extension tube is connected via a thread to the mill/bit unit 62.

FIG. 11 illustrates a standard anchor with a lug 64. The anchor is equipped with drag blocks to center the assemblies in the casing. The anchor is connected to the downhole tool via a threaded connection 63. The diameter of the anchor 64 mates with the casing inserted nipple ID.

Metallic particles are often present in the main borehole. Metallic particles can be harmful to the downhole tool. FIG. 12 illustrates a magnetic hole cleaner 66. The system is a tube section equipped with a female end connection 67 and a male end connection 68. The magnets collect and retain the metallic particles in a method, which will not cause harm to the downhole tools.

FIG. 13 illustrates the cutting tool guide. Above the magnetic hole cleaner is a casing departure sub 69. The casing departure sub 69 has a female end connection 70 and a male end connection 71. The casing departure sub 69 provides a guide for the casing cutting system to operate.

FIG. 14 illustrates a hex sub 72. The hex sub 72 is connected to the downhole tool via threaded female end connection 73 and male end connection 74. The hex sub 72 is placed in the assembly to guide the tube in a specific direction.

FIG. 15 illustrates the guide tube 76, which is employed to extend a specific distance from the main casing allowing a specific angle to be accomplished. The guide tube 76 is constructed of a composite material having a low modulus which allows bending, loading along the axis to be very small. The method in which the filaments are placed dictates the strength of the tube during bending. The hex guide tube 76 is fitted with a threaded connection 75. The threaded connection accommodates a bearing assembly 54 as illustrated in FIG. 15A. The hex section 77 has an arrangement of filaments, which result in a high degree of torsional strength. Deflection along the length of the tube must be very small to guide the cutting of the micro-borehole. A disconnect device 55 illustrated in FIG. 15B is connected to the threaded section opposite to Item 75.

FIG. 16 illustrates the closed end of the downhole tool. The outer body is equipped with a locking lug 78. The housing 79 illustrate the outer body. An extension tube guide 80 is fitted above the downhole tool.

The casing insert mill/bit is illustrated in FIG. 17. The mill/bit has several major components. The mill/bit 86 is connected to the extension tube assembly by a female end connection 89. Special jets are fitted at location 85 and 83. The jets are employed in some formations to “jet” the formation manufacturing the micro-borehole. In harder formations, the mill/bit must remove the material via a milling process. PDC or hardened cutters are mounted onto the mill/bit as illustrated in Item 84. The mill/bit is designed to drill a minimum of 21 holes through the casing prior to replacement.

FIG. 18 illustrates the lower section of the extension tube 87 which is equipped with a female end connection 89. The lower extension tube 87 must have special qualities, which allow bending in the axial direction, but must support a compression drilling load. The lower extension tube 87 is equipped with spherical supports 88. The supports provide lateral support of the extension tube. The spherical supports 88 are welded to the alloy tube via an electron beam welding system.

Electron-beam welding prevents major heat changes to occur with regards to the alloy tube. Heat changes will distort the use of the extension and can cause failure in the heat effective zone. FIG. 18A illustrates the lower extension tube connection 92. The upper end of the lower extension tube is connected to the upper extension tube via a threaded male connection 91. The threaded body is connected to the mill/bit via an electron-beam weldment.

FIG. 19 illustrates the upper section of the extension tube 94. The upper extension tube 94 is connected to a threaded connection 93. The initial cavity is tapered to allow fluid preparation before entering the lower extension tube 87.

FIG. 20 illustrates the upper extension tube safety tube 98. The tubes are constructed in lengths of 30′ and have flush OD connections 97 and 99. The tubes have an internal operating pressure of 20,000 psi. The tubes are constructed of BeCu material. The extension outward into the formation will cause a member of the extension tube to be employed.

FIG. 21 illustrates the assembly view of the downhole tool. The work string 59 enters the extension tube guide 80 located in the within safety tube 98. The extension tube 87 is connected via flush OD connections 97. This passes through the guide tube 76 which is connected to the hex sub 72. The end of the extension tube 87 is connected to the mill/bit 62. The guide tube 76 is connected to the casing departure sub 69 which is connected to the magnetic hole cleaner 66 and held stationary via the anchor lug 64.

FIG. 22 illustrates the guide tube 76 to be extended into the formation. The mill/bit 86 has cut the formation to allow passage of the guide tube. FIG. 22 also illustrates the upper level of the formation 5 and the lower level of the formation 6. The main borehole casing 4 is also illustrated.

FIG. 23 illustrates the oil and gas formation with upper level 5 and lower level 6. Between Items 5 and 6 is the oil or gas bearing formation. FIG. 23 illustrates the guide tube 76 extended in a radius mode with the lower and upper extension tubes fully extended. The main casing 4 is illustrated. FIG. 24 illustrates a completed micro-hole exhibiting the radius turn 100 and the horizontal leg 101.

Operational Procedures of the Invention

The micro-borehole process allows enhancement of oil and gas wells. The process can be employed in different well conditions throughout the world. The oil and gas reserves throughout the world have harvested approximately 25% of the oil found. Hence, there is 75% of the discovered oil remaining to be harvested. The quest is to produce the “locked in” oil and gas is being conducted throughout the world. In the recent time period certain formation “shales” are being produced in vast quantities. In order to produce the shale formation, a fracking process is required, which is deemed to be harmful to humans.

The invention being considered allows the production of “shale” and other “tight” formations to be produced at an efficient level. The invention teaches a method to control the enhancement process. The following procedure is employed in the manufacture of micro-boreholes:

Procedure 1

The well to be considered is prepared for the micro-borehole installation. Production tubing is pulled, the well internal surfaces are cleaned and residual fluids are pumped out. The well bore is gauged and the casing collars are identified via well logs.

Procedure 2

A well plan is formulated to install the micro-borehole in a specific area and direction about the borehole.

Procedure 3

The invention (downhole tool) is prepared to accommodate the requirements of the well enhancement. (Steel casing application)

Procedure 4

In new wells, the carbon fiber inserts are inserted into the casing string as per the specifications. (New well conditions with inserts)

Procedure 5

The downhole tool is lowered to the production zone within the well. By instruments (gamma ray technology), the oil-bearing areas are identified and located.

Procedure 6

In wells with inserts, the placement of the inserts defines the area in which the micro-holes will be provided. In wells without inserts, the gamma ray tool will locate the exit points within the main well bore to provide micro-boreholes.

Procedure 7

Once the tool is anchored within the casing, the process can start. Pump pressure is elevated to a level of 3500 psi. The pressure releases the lock assembly allowing the extension tube and guide tube to be free of the tool body.

Procedure 8

The pump pressure is elevated to 20,000# psi. The power swivel is engaged to the desired speed and torque.

Procedure 9

The advancement of the mill/bit is started from the surface controls. Depending on the formation strength, the rate of penetration is set.

Procedure 10

As the advancement of the mill/bit occurs and surface indication illustrates that the mill/bit has departed the stowed location.

Procedure 11

The mill/bit advances outward with the guide tube which is set at 5°/foot angle. As the guide shoe extends outward, a borehole radius is formed. Once the guide tube is extended outward to its limit (30′-0″), the guide tube is disconnected from the extension tube.

Procedure 12

Once the guide tube is disconnected from the extension tube, the rate of penetration is increased to meet the drilling plan rate of penetration.

Procedure 13

Once the micro-hole is formed due to the length limitation, the movement of the extension tube is stopped. Fluid is pumped to remove any material from the micro-borehole.

Procedure 14

Once the pumping is completed, the pressure is reduced to 3500 psi. The rotation remains active throughout the process.

Procedure 15

The extension tube is extracted from the micro-borehole. Once the automatic disconnect is re-engaged, the guide tube and extension tube moves up the hole together.

Procedure 16

Once the extension tube and guide tube reach the stowed position, a surface indication allows the operator to know that the process is complete and that a micro-hole has been completed.

Procedure 17

The operator must follow the drilling plan. The anchor is unlocked and repositioned at a new location. A minimum of 20 micro-boreholes can be provided in one trip into the main borehole.

Procedure 18

In the event that the carbon fiber inserts are not employed, the steel casing can be parted. Due to the steel, material between 3 and 4 micro-holes can be provided considering one trip into the hole.

The general extension and guide tube procedures are identical in both the carbon fiber insert method and the steel casing method. 

1. A downhole drilling system for drilling micro-holes in earth formations comprising: a surface control unit which programs the action of the downhole tool and provides high-pressure fluid pressure to the downhole tool which in turn, by robotic action, parts the casing and drills a micro-hole to a general location, which is pre-programmed from the surface for the enhancement of oil and gas production.
 2. A method of claim 1 to extend a micro-borehole outward into an oil and gas formation allowing the general attitude of the borehole to be as planned and to rotate the vertical borehole to a horizontal borehole in a distance less than 30′-0″.
 3. A system of claim 1 of casing inserts which are mounted into the standard protective casing allowing the inserts to be placed in a planned location allowing the casing string to be parted employing a mill/bit, which, due to the insert material, allows many cycles to occur without replacement of the mill/bit downhole.
 4. A method in which a hex-shaped guide tube is allowed to exit the casing into the formation cased into the formation allowing a pre-determined radius to be formed by the mill/bit, which extends into the oil and gas formation and the radius is formed via the bent section located at the end section of the extension tube.
 5. A guide tube as set forth in claim 4, which is constructed of a carbon fiber material or the like, which has strength qualities in torsion resistance of a high magnitude and the axial bending is of very low resistance thereby allowing the guide tube to retain its tolerance when loaded by torsional forces and will bend an axial load at a very low magnitude of force.
 6. The extension tube is equipped with a disconnect assembly which allows the tube to assist in providing a 90° turn and by a robotic event allows the drilling string to go forward into the formation at a given angle to a pre-determined distance and return to the guide tube all allowing retraction of the guide tool into the downhole tool.
 7. A mill/bit to be employed for the purpose of parting the casing and extending outward into the formation causing a micro-borehole to be found at a specific distance from the protection casing.
 8. A mill/bit extension tube as set forth in claim 6 is provided to allow the rotating assembly to bend to the shape and direction of the guide tube by employing a special alloy such as NiTi material having a small tube diameter resulting in a small section modulus and having mounted along the axis spherical guides which supports the small diameter tube and provides lateral stability of the extension tube which is loaded by compression forces.
 9. A system which allows the extension tube as set forth in claim 6 to be disconnected from the guide tube in an automatic and robotic fashion and once the guide tube is disconnected, the extension tube is allowed to travel to the designated distance and once the extension tube has completed its travel, it is extracted causing the extension tube to reenter the tool casing causing the guide tube to also be retracted into the tool casing.
 10. A system which allows the downhole tool to be located at different intervals along the axis of the casing employing the landing nipples to be engaged thereby locating the micro-hole formation and to anchor the tool to avoid any axial movement. 11-13. (canceled)
 14. A drilling system, which provides completion fluids to be cleaned from solids at a level lower than 5 microns thereby allowing the formation to be clear of any particles, which are introduced from the completion fluids.
 15. A drilling system, as set forth in claim 8 which indicates the cycle milestones, which have been completed, and identifies the completion of the drilling event.
 16. (canceled)
 17. A drilling system as described in claim 9, which allows the placement of clusters of micro-boreholes to replace oil and gas formation fracking process with a controlled and predictable program employing micro-boreholes. 